Paper web transfer device utilizing suction box



C. SCHIEL April 29, 1969 PAPER WEB TRANSFER DEVICE UTILIZING SUCTION BOXFiled Jan. 21, 1966 INVENTOR. QHRISTIAN SCHIEL United States Patent Int.01. D21f 1/52 US. Cl. 162306 Claims ABSTRACT OF THE DISCLOSURE Anarrangement for transferring a wet web from the wire of a papermakingmachine to a porous belt-like conveyor member in which a stationarysuction box is mounted adjacent and parallel to the wire of thepapermaking machine and has a convex perforated region on the sidenearest the wire and which region engages the back of the conveyormember and supplies suction therethrough to pick up the web from theWire and to transfer it to the conveyor member. The conveyor member mayhave a wear resilient surface on the suction box side and this surfacecan be in the form of a belt-like member separate from the web engagingside of the conveyor member which can also be a belt-like member.

The present invention relates to paper making machines, particularly ofthe Fourdrinier type, and is most particularly concerned withtransferring of the wet Web from the wire of the paper making machine toa pick up and conveyor member, such as a felt, which carries the web toa drying section.

In particular, the present invention relates to an improved arrangementfor effecting the transfer of the wet web from the wire of the papermachine to the conveyor member, or felt, in such a manner that there islittle loss of fiber from the paper web and the paper web is transferredfrom the wire to the felt in the best possible condition.

The transferring of a wet web from the wire of a paper making machine,such as a Fourdrinier machine, to a felt on which the web is conveyed tothe drying section of the machine is, of course, known.

One matter of accomplishing the web transfer is to employ a pick-up rollfor picking up the paper web from the wire in which the pick-up rolloperates under suction. It has been found, however, that the perforatedcylindrical surface of such a pick-up roll will impart spots, somewhatlike watermarks, to the web of paper where the web is aligned with thesuction holes in the roll. The direct suction action on the paper alsointroduces the possibility of damaging the surface of the paper and alsocreates the possibility that the paper will tear when picked up from thewire of the machine. Such perforated suction rolls are also quiteexpensive and the driving of the roll at the proper speed is diflicultand is well known that such rolls are quite noisy in operation.Considerable power is also required for maintaining the proper degree ofsuction inside vacuum pick-up rolls of this nature.

Another type of pick-up which is known utilizes two guide rolls whichguide the felt and which enclose between each other a suction box whilethe rolls press the felt, which is subjected to the vacuum of thesuction box, against the paper web to be picked up along a short arc inthe region of the end of the suction zone of the couch roll, or shortlybeyond the said region. The two rolls are adjustable with respect toeach other and are tilted inwardly and outwardly together along with thesuction box.

3,441,476 Patented Apr. 29, 1969 This construction involves severaldisadvantages including the fact that two rotating rolls are requiredeach of which must have at least two bearings while roll driving meansmust be provided. Since such rolls are relatively large and involvelarge masses, vibration or oscillating of the rolls can occur which willmaterially effect the picking up of the paper web from the wire of thepaper making machine. The picking up of the web is a rather delicateoperation and any disturbance thereof is apt to lead to tearing, orotherwise damaging, of the web.

The adjustment of the rolls to the correct position to seal the vacuumspace therebetween is also difficult and, furthermore, the adjustingmeans required for this purpose are expensive.

Another arrangement for picking up a web from the wire of a Fourdriniermachine is illustrated in Patent No. 3,207,65 8. In this patent, amember having a tip of small curvature, less than three inches radius ofcurvature, bears with the said tip on the back of the pick-up felt atthe pick-up point and presses the pick-up felt against the wire of thepaper making machine. The felt and wire approach each other on one sideof the member, meet at the tip of the member, and diverge from eachother on the other side of the member. The member bearing on the feltmay be stationary or it may include a small roller forming the said tipand driven in rotation so as to roll on the back of the felt.

In the structure of this patent, a problem exists in effecting thesubstantially complete transfer of the web from the wire to the feltwithout any difiiculties merely by pressing the felt against the wirecarrying the paper web. The member which bears on the felt, according tothe United States patent, has a relatively small radius of curvature inorder to develop the pressure necessary between the felt and the wire toeffect pick-up of the web and, accordingly, a good possibility existsthat the member will wear rapidly when it is stationary mounted and,also, considerable pressure is exerted on the felt, due to the smallradius of curvature and this will also induce strain and wear in thefelt. The tension of the wire of the paper making machine must becontrolled closely to maintain the proper pressure at the pick up regionwithout, however, overstressing the wire.

When the device of the said patent includes a roller rolling on thefelt, the roller is so small in diameter as to require additionalsupport because of the great relative width of the machine and thisinvolves added expensive structure in the form of a machined back-upmember to prevent the small roller from deflecting during operation.

Having the foregoing in mind, the present invention proposes theprovision of an arrangement for effecting the transfer of a moist paperweb from the wire of paper making machine, such as a Fourdriniermachine, to a conveyor member such as a felt in which the disadvantagesreferred to above in connection with known transfer arrangements iseliminated.

A particular object of the present invention is the effecting of thetransfer of the web from the wire to the felt by the use of a stationarysuction box acting through the conveyor member.

Another object is the provision of an arrangment for transferring a wetpaper web from the wire of a paper making machine to a conveyor felt inwhich the structure employed is quite simple, avoiding rotating partsand bearings therefor and drive means therefor so that the installationis relatively inexpensive.

Another object of this invention is the provision of a pick-uparrangement of the nature referred to which is located along the wire ofthe paper making machine at a spot between the couch roll and thedriving roller so that the wire is engaged by the conveyor member orfelt along an unsupported region of the wire so that the suction exertedin the pick-up device is fully effective for picking up the web from thewire.

Still another object is the provision of a suction type pick-up fortransferring a wet paper web from a paper making machine wire to aconveyor member, or felt, in which the paper web and the wire of thepaper making machine, as well as the conveyor member or felt, areprevented from being subjected to high pressure so that damage theretodoes not result and so that where foreign matter such as lumps of pulpor dirt might accidently become entrained in the paper web, there is nodamage to the parts of the structure because the wire can easily yieldto pass such foreign matter.

The above mentioned objects and advantages of the present invention asWell as still other objects and advantages thereof will become moreapparent upon reference to the following specification taken inconnection wtih the accompanying drawing in which:

FIGURE 1 is a somewhat schematic sectional view showing the fundamentalset up of the present invention, utilizing a suction box over which theweb pick-up conveyor member slides;

FIGURE 2 is a view similar to FIGURE 1 but shows a cylindrical suctionbox; and

FIGURE 3 is a somewhat diagrammatic view showing the complete pick-upportion of a paper making machine with a suction box according to thepresent invention and also showing the use of a supporting member withthe pick-up felt.

In the practice of the present invention, a non-rotatable suction box isemployed over which the member which is to pick-up the wet paper webslides. The suction box holds the pick-up member in close proximity withthe paper machine wire along an unsupported section of the wire betweenthe couch roll and the driver roll of the paper making machine, whichlast mentioned roll is located where the wire of the machine turns toreturn toward the head box end of the machine.

According to the present invention, the pick-up member may comprise aconventional endless felt or it may also consist of a compound member inwhich the side or layer thereof which slides on the suction shoe isparticularly constructed to resist wear and abrasion and to slide freelyon the suction shoe While the other side or layer thereof which engagesthe paper web is particularly constructed for that specific function.

For example, the side of the pick-up member which slides on the suctionshoe may be constructed of polyamide or polyester fibers which willslide easily on the suction shoe and resist wear even when woven to forma porous member through which the suction of the shoe can act. The shoeitself, of course, is manufactured of a material which will resist wear,such as an alloyed steel or the like, and which material can also take aflnish so as to present a smooth surface to the member slidingthereover.

The present invention further permits the separation of the pick-up andconveying member into two parts which include a lower or innersupporting member which slides directly on the suction shoe, and anupper or outer member which is the actual pickup member itself. Witheither a compound member, or a two part member, a separation offunctions is thus introduced which makes it possible that each of thetwo parts referred to may be constructed of those materials which arebest suited to the particular function of the respective part.

The further advantage exists that only the supporting member which isthe one most subjected to wear and abrasion when it slides over thesuction box, needs to be replaced from time to time, while the upper orouter member or felt is free of such abrasion and will last for a longtime. The upper or outer member, furthermore, may be made so that itwill be highly absorbent to water and thereby improve the treatment ofthe paper web.

The inner or supporting web may also serve as an auxiliary wire forremoval of water and to this end may be provided with correspondingpores or may be constructed so as to have a relatively open mesh. Thesignificance of the supporting web is that it serves simultaneously asthe fabric in the fabric press 10, 11 of FIGURE 3. Such a fabric, whichmay consist of incompressible meshes of a polymer, is employed in modernpressing technology; it serves the purpose of picking up a portion ofthe water which is squeezed out of the fibrous web, and in this way,avoids the migration of too much moisture back into the pressing felt 5which truly does the pressing in the correct sense of the word. Thewater which is retained in the meshes of the supporting web 8 is removedby, blowing, for example, after the web 8 has left the pressure zone.The supporting web thus serves simultaneously as the fabric of thefabric press.

A still further advantageous possibility exists in that no true feltneed to be used in the pick-up of a paper web because the pick-up isaccomplished by the application of the suction through the supportingmember and which member, as mentioned, need not be felted but is soconstructed that it is highly porous and resists abrasion and slidesfreely on the suction shoe. The outer member which directly contacts thepaper web may, of course, be a felt.

By having the suction shoe or suction box stationarily mounted, thesuction zone thereof, which is formed by providing the box or shoe withperforations, extends only over that portion of the shoe engaged by thepick-up member so that the maintaining of a high degree of suctionwithin the box or shoe is a relatively simple matter.

Referring now to the drawings somewhat more in detail, in FIGURE 1, wire1 of a paper making machine is guided over couch roll 2 and thedeviating or reversing roll 3, and which is also a driving roll. Wetpaper web 4 is disposed on wire 1.

A pickup and conveying member 5 is guided over a stationary hollowsuction shoe or suction box 6 so as to make contact with paper web 4 ata point therealong located between couch roll 2 and deviating orreversing roll 3. The paper web 4, due to the influence of suction box 6is transferred at that point to conveying member 5.

The suction box 6 is provided with holes 7 extending therethrough andcommunicating with the back of member 5. These holes are distributedover the region where the paper web 4 is picked up and extend laterallyacross the entire width of the felt or member 5 where the paper web isto be picked up. Suction is developed within the suction box or shoe 6by way of connection 8 which is connected to a suitable source ofsuction. Connection 8 is so located at the bottom of the suction shoe asto serve also as a drain connection for water drawn into the shoe.

In FIGURE 2, substantially the same arrangement is illustrated and thesame reference numerals are employed except that in FIGURE 2 the suctionbox or suction shoe, designated 6a, is a hollow cylinder instead ofbeing of the configuration shown in FIGURE 1.

In both of the modifications of FIGURES 1 and 2 water which is drawnthrough member 5 and into the suction box or shoe runs to the bottomthereof and can fiow off via connection 8.

FIGURE 3 is a view showing more completely the pickup section accordingto the present invention. In FIG- URE 3 wire 1, as before, passes aboutthe couch roll 2 and deviating or reversing roll 3 and carries the wetpaper web 4, which is designated by the dotted lines in FIGURE 3. Thepick-up member in FIGURE 3 consists of an outer endless member 5 in theform of a pick-up felt and an inner supporting member 8 which may be afabric-like member of a different character than member 5. Member 8 isshown as a dashed line.

The members 5 and 8 converge and pass as a unit in face to faceengagement about suction shoe or box 6a and then continue as a unit andwith the paper web 4 adhered thereto about the deviating roller 9 andthen pass through a press section consisting of rolls and 11.

Web 4 is drawn off from roll 11, whereas member 5 continues from rolls10 and 11 along an independent path and passes about a series of idlerrolls and then returns through the two rolls 12 and 13, forming awashing press, and then again passes to suction box 6a. The inner orsupporting member 8 on the other hand, separates from pick-up member 5as the members leave rolls 10 and 11 and passes along an independentpath about its own idling rolls and then returns to the suction box 6awhere it again joins with the pick-up member 5.

It will be understood that the showing in FIGURE 3 is only exemplary ofdifferent arrangements that could be made and that the Washing section12 and 13 is not essential in all cases.

FIGURE 3 illustrates what might be done when the pick-up member 5 andsupporting member 8 are constructed of different materials. Member 8 forexample, can be made from polyamide or from polyester fibers and isrelatively porous for the free passage therethrough of suction andwater. Member 5, on the other hand, is more in the nature of aconventional felt in that it presents a surface to the paper which willnot damage the paper in any way. Member 5, however, does not have tohave the characteristics of a felt, as this term is generally employedin the paper making art, because the transfer of the web thereto isaccomplished by suction from the suction box or suction shoe and not inthe manner that a paper web is usually transferred to a felt conveyormember by the application of pressure between the paper web and the feltmember.

It will be understood, further, that the wire 1 of the paper makingmachine is quite porous whereas the paper Web 4 is relatively dense andthat, therefore, the application of suction through the pick-up memberto the paper web 4 will cause the paper web readily to be picked up fromthe wire with substantially no fibrous residue remaining on the wire.The transfer of the web from the paper making machine to the pick-up andconveying member 5 is thus relatively complete at all times resulting inhighly efficient operation of the arrangement.

Still further, since the transfer of the paper web is effected bysuction there is no need to add water at any time to the pick-up member5 as is sometimes necessary with other types of pick-up devices notemploying suction.

The device of the present invention operates well at any speed and is aseffective for picking up thin webs as it is for picking up thick webs.In operation, no adjustments need be made except, possibly, to vary thedegree of suction in the suction box or shoe.

It will be understood that this invention is susceptible to modificationin order to adapt it to different usages and conditions and accordingly,it is desired to comprehend such modifications within this invention asmay fall within scope of the appended claims.

What is claimed is:

1. In a paper making machine having a porous belt on which a fibrous webis formed and rolls supporting said porous belt and a porous belt-likeconveyor member operable for picking up said web from said porous beltin a region extending transversely of said porous belt and for conveyingthe web to a following work station, said region being located betweensaid rolls where said porous belt is unsupported, said conveyor memberconverging With said porous belt on one side of said region anddiverging therefrom on the other side of said region and running in thedirection and at substantially the same linear speed as said porous beltin said region, said conveyor member engaging the exposed side of theweb in said region, and a stationary nonrotatable member relativelysmall in cross section extending transversely of said conveyor memberand supportingly and slidingly engaging the back of said conveyor memberin said region and guiding said conveyor member into and out of andthrough said region, said stationary member being in the form of asubstantially rigid hollow box, the surface of said box which engagesthe back of said conveyor member being curved so as to be convex towardsaid porous belt at least over the range of said region, a suctionconnection to said box to develop suction therein, and apertures in saidbox distributed longitudinally and arcuately over the transverse exentof said region and over substantially the arcuate extent of said region,said apertures communicating with the back of said coveyor member atleast in said region thereby to exert suction through said conveyormember on said web to effect transfer of the web from the porous belt ofsaid paper-making machine to said conveyor member.

2. The combination according to claim 1 in which the said rollssupporting said porous belt include a couch roll and a driving rollspaced therefrom, and said stationary member being positionedsubstantially midway between said rolls so that the said region wherethe web is picked up is about in the middle of the reach of the porousbelt exltfnding between the said couch roll and the said driving ro 3.The combination according to claim 1 in which said rolls have their axeshorizontal and said stationary member has its longitudinal axishorizontal and said suction connection is located in substantially thelowest portion of said stationary member whereby water drawn into saidstationary member through said apertures as the said web is picked upcan be drained from said stationary member.

4. The combination according to claim 1 in which said conveyor member istwo sided and comprises a wear resistant portion on the side engagingthe said surface of said stationary member and a felt-like portion onthe side which engages said web.

5. The combination according to claim 4 in which said wear resistantportion is a material formed of synthetic fibers such as polyamide orpolyester fibers.

6. The combination according to claim 1 in which said conveyor member isa substantially incompressible, porous belt-like member resistant towear.

7. The combination according to claim 1 in which said conveyor membercomprises an inner belt which slides on said member and an outer beltseparate therefrom which engages said web.

8. The combination according to claim 1 in which said conveyor membercomprises an inner belt which slides on said member and an outer beltseparate therefrom which engages said web, and means guiding said innerbelt and outer belt for movement in face to face relation into andthrough and out of said region where the web is picked up and to thefollowing work station and along independent paths from the exit of saidwork station to the entrance to said region.

9. The combination according to claim 7 in which said inner belt is inthe form of a seine-like element through which air and water can freelymove.

10. The combination according to claim 1 in which said stationary memberis in the form of a hollow cylinder.

References Cited UNITED STATES PATENTS 2,709,398 5/1955 Beachler l62206DONALL H. SYLVESTER, Primary Examiner.

A. C. HODGSON, Assistant Examiner.

US. Cl. X.R. l394l0

